<?php

/**
 * @package dompdf
 * @link    http://www.dompdf.com/
 * @author  Benj Carson <benjcarson@digitaljunkies.ca>
 * @author  Helmut Tischer <htischer@weihenstephan.org>
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @version $Id: list_bullet_positioner.cls.php 448 2011-11-13 13:00:03Z fabien.menager $
 */

/**
 * Positions list bullets
 *
 * @access private
 * @package dompdf
 */
class List_Bullet_Positioner extends Positioner {

    function __construct(Frame_Decorator $frame) {
        parent::__construct($frame);
    }

    //........................................................................

    function position() {

        // Bullets & friends are positioned an absolute distance to the left of
        // the content edge of their parent element
        $cb = $this->_frame->get_containing_block();

        // Note: this differs from most frames in that we must position
        // ourselves after determining our width
        $x = $cb["x"] - $this->_frame->get_width();

        $p = $this->_frame->find_block_parent();

        $y = $p->get_current_line_box()->y;

        // This is a bit of a hack...
        $n = $this->_frame->get_next_sibling();
        if ($n) {
            $style = $n->get_style();
            $line_height = $style->length_in_pt($style->line_height, $style->get_font_size());
            $offset = $style->length_in_pt($line_height, $n->get_containing_block("h")) - $this->_frame->get_height();
            $y += $offset / 2;
        }

        // Now the position is the left top of the block which should be marked with the bullet.
        // We tried to find out the y of the start of the first text character within the block.
        // But the top margin/padding does not fit, neither from this nor from the next sibling
        // The "bit of a hack" above does not work also.
        // Instead let's position the bullet vertically centered to the block which should be marked.
        // But for get_next_sibling() the get_containing_block is all zero, and for find_block_parent()
        // the get_containing_block is paper width and the entire list as height.
        // if ($p) {
        //   //$cb = $n->get_containing_block();
        //   $cb = $p->get_containing_block();
        //   $y += $cb["h"]/2;
        // print 'cb:'.$cb["x"].':'.$cb["y"].':'.$cb["w"].':'.$cb["h"].':';
        // }   
        // Todo:
        // For now give up on the above. Use Guesswork with font y-pos in the middle of the line spacing

        /* $style = $p->get_style();
          $font_size = $style->get_font_size();
          $line_height = $style->length_in_pt($style->line_height, $font_size);
          $y += ($line_height - $font_size) / 2; */

        //Position is x-end y-top of character position of the bullet.    
        $this->_frame->set_position($x, $y);
    }

}
